Can you give http://patchwork.freedesktop.org/patch/31650/ a try ?
It brings us back to the original behaviour by dropping the headers as scons parses through the list. It will also allow us to put all headers in makefile.sources and (one day) have a fully working automake 'make dist' :)

(In reply to comment #3)
> Can you give http://patchwork.freedesktop.org/patch/31650/ a try ?
>
> It brings us back to the original behaviour by dropping the headers as scons
> parses through the list. It will also allow us to put all headers in
> makefile.sources and (one day) have a fully working automake 'make dist' :)
This patch fixes the build error for me.
Tested-by: Vinson Lee <vlee@freedesktop.org>